The present invention relates to a portable sprayer having a backpack on which are secured a blower unit and a supply unit for a spray agent.
Portable sprayers of the aforementioned type are used in the fruit, wine and vegetable industries for the application of plant protection agents. In the supply tank, a plant protection agent that is placed therein is made available for the spraying process. By means of the blower unit, an air stream is produced that discharges the spray agent out of the supply tank, atomizes it and supplies it to the plants that are to be treated. For different applications, plant protection agent in the form, for example, of a liquid, a powder, or a granulate, is provided.
To keep the effect of vibration on the operator low, the motor-blower unit of such sprayers are isolated from the backpack with respect to vibrations via an anti-vibration system. With known configurations, the blower unit is mechanically separated from the supply tank. At least one anti-vibration element is provided, by means of which the blower unit is suspended from the backpack. The anti-vibration element or elements are such that over the operating range of the excitation frequencies that are to be anticipated, as good a vibration isolation as possible results. The mechanically separated supply tank is independently secured to the backpack.
It has become evident that the aforementioned vibration isolation, which is optimized for operation with liquid spray agent, is suitable only to a limited extent for the application of pulverous or granular material. For the application of such material from the supply tank, a certain level of vibration is advantageous. Appropriately optimized configurations provide a mechanical coupling of the supply tank with the blower unit for the application of solid plant protection agent. Vibrations of the drive motor, which is embodied as an internal combustion engine, and which vibrations are caused by operation, are transferred to the supply tank and to the material stored therein. The level of vibration at the tank prevents the formation of clumps or other mechanisms for the accumulation of material in the supply tank, thereby facilitating a fine-grained charge out of the tank and into the motor-driven blower.
A rigid connection of the supply tank with the blower unit leads to the increase of the oscillating or vibrating mass. Therefore, for an effective vibration isolation, the anti-vibration elements between the blower unit and the backpack must be made correspondingly more rigid.
If it is not desired to provide two different sprayers for the application of liquid material on the one hand or pulverous granular material on the other hand, it is necessary, for the respective application, to provide an expensive conversion along with the labor associated therewith. The soft anti-vibration (AV) suspension provided during operation with liquid material is too soft for the coupling-on of the supply tank for the application of pulverous or granular material due to the additional mass of the supply tank. A more rigid AV setting for the vibrationally mechanical unit composed of blower unit and supply tank for the application of pulverous or granular material is, in contrast, too stiff for the conversion to a supply tank, for liquid material, that is mechanically separated from the blower unit, and leads to undesirably high vibrational stressing of the operator during the application of liquid material.
It is therefore an object of the present invention to improve a portable sprayer in such a way that, while providing a universal usability for the application of liquid and pulverous or granular material, it is possible, with little conversion expense, to respectively achieve a high carrying and operating comfort for the user.